Guest: Alfred Zaehringer. Topics: rocket science, rocket equation, Mars, chemical rockets, space tourism, low cost space access. Al Zaehringer returned to The Space Show to discuss his two books. Al was the editor of "Rocketscience: The Journal of the Detroit Rocket Society, Inc. 1947-1952," which is available from http://www.apogeebooks.com. This is a must have reference book, one of the very best of its kind.